Why are you not allowed to turn off the road now?

You are correct: you must not turn off the road now because of the oncoming red car (answer 1). In Germany, when overtaking or preparing to pass an obstacle like a stopped bus, you must always give way to oncoming traffic. The oncoming vehicle has priority, and it would be dangerous and illegal to turn or move into their lane before they have passed. Only when the oncoming lane is completely free and it is safe to proceed may you overtake or turn. Always check carefully for approaching vehicles to avoid any collision risk.